The etching and depositing process in the field of microelectronic processing means that micro particles (mainly including ions and neutral particles) in a cavity interact with a substrate to be processed to complete the processing process. This is a typical trans-scale process, in which nano-scale or micron-scale processing is completed through etching and depositing of micro particles on atom scale.
The processing cost of etching and depositing is very high, so computer simulation becomes effective means in order to deeply understand process engineering. However, due to the trans-scale characteristic of this process, a lot of difficulties are brought to the simulation process.
Currently, common simulation methods for etching and depositing a profile mainly include a cellular automaton, a string algorithm, a level set and the like, and in such methods, etching yield or etching (depositing) rate and other parameters of a certain particle for a substrate is input to accomplish surface evolution. However, in applications, these parameters are often difficult to obtain, meanwhile, as these parameters actually are dynamically changed due to continuous change of a processing environment in practical processing, it is inaccurate to use fixed parameters to perform simulation in a traditional simulation method. Meanwhile, in the aspect of presenting simulation results, a macro method can reflect the evolution process of a whole profile, can be used for researching microgroove etching, nonuniform depositing coverage and other phenomena, but cannot completely express a micro process, such as generation of an amorphous layer in the etching process.
When atom-scale simulation is performed on a micro scale, a molecular dynamics or monte-carlo method is often used. Such methods perform systematic evolution towards a certain trend (such as the minimum energy) through a given potential function (or probability of various behaviors on surfaces of the particles) and other evolution rules and through interaction of incident particles and atoms of the substrate. This method has the characteristics that the micro particle evolution process can be described, but the time and space scales obtained through computation are very small, and the requirement of large-scale computation cannot be met.